tailieunhanh - Impact of parallel computing on study of time evolution of a quantum impurity system in response to a quench

In this paper, we estimate the scale of time consumption of such calculation in comparison to that of time-independent calculation, and present our solution to the problem by using parallel computing as implementing both MPI and OpenMP to the calculation. We also discuss the possibility to exploit parallel computing with GPU in the near future, and the preliminary results of time-dependent spectral function. | VNU Journal of Science Mathematics Physics Vol. 36 No. 1 2020 38-45 Original Article Impact of Parallel Computing on Study of Time Evolution of a Quantum Impurity System in Response to a Quench Nghiem Thi Minh Hoa1 2 Dang The Hung1 3 Luong Minh Tuan4 Duong Xuan Nui5 Nguyen Duc Trung Kien6 1 PHENIKAA Institute for Advanced Study PHENIKAA University Ha Dong Hanoi Vietnam 2 Faculty of Basic Science PHENIKAA University Ha Dong Hanoi Vietnam 3 Faculty of Materials Science and Engineering PHENIKAA University Ha Dong Hanoi Vietnam 4 National University of Civil Engineering Dong Tam Hai Ba Trung Hanoi Vietnam 5 Vietnam National University of Forestry Xuan Mai Chuong My Hanoi Vietnam 6 Advanced Institute for Science and Technology HUST Bach Khoa Hai Ba Trung Hanoi Vietnam Received 11 January 2020 Revised 19 February 2020 Accepted 25 February 2020 Abstract In an arbitrary system subjected to a quench or an external field that varies the system parameters the degrees of freedom increases double in comparison to that of an isolated system. In this study we consider the quantum impurity system subjected to a quench and measure the corresponding time-evolution of the spectral function which is originated from the time-resolved photoemission spectroscopy. Due to the large number of degrees of freedom the expression of the time-dependent spectral function is twice much more complicated than that of the time-independent spectral function and therefore the calculation is extremely time consuming. In this paper we estimate the scale of time consumption of such calculation in comparison to that of time-independent calculation and present our solution to the problem by using parallel computing as implementing both MPI and OpenMP to the calculation. We also discuss the possibility to exploit parallel computing with GPU in the near future and the preliminary results of time-dependent spectral function. Keywords Quantum impurity system time-dependent spectral function degrees of freedom